2008 YAMAHA TTR50 engine

TABLE OF CONTENTSSAFETY INFORMATION ..................1-1
Safe riding ......................................1-1
Location of important labels ............1-4
DESCRIPTION ..................................2-1
Left view ..........................................2-1
Right view ........................................2-2
Controls and instruments.................2-3
INSTRUMENT AND CONTROL
FUNCTIONS.......................................3-1
Main switch .....................................3-1
Handlebar switches ........................3-1
Speed limiter ...................................3-2
Shift pedal .......................................3-2
Brake lever .....................................3-3
Brake pedal ....................................3-3
Fuel tank cap ..................................3-3
Fuel .................................................3-4
Fuel tank breather hose ..................3-5
Fuel cock ........................................3-5
Starter (choke) lever .......................3-6
Seat ................................................3-7
Sidestand ........................................3-7
Starting circuit cut-off system .........3-8
PRE-OPERATION CHECKS..............4-1
Pre-operation check list ..................4-2OPERATION AND IMPORTANT
RIDING POINTS................................. 5-1
Starting and warming up a cold
engine ......................................... 5-1
Starting a warm engine .................. 5-2
Shifting ........................................... 5-2
Engine break-in .............................. 5-3
Parking ........................................... 5-4
PERIODIC MAINTENANCE AND
MINOR REPAIR................................. 6-1
PERIODIC MAINTENANCE ........... 6-1
Periodic maintenance chart for
the emission control system ....... 6-2
General maintenance and
lubrication chart .......................... 6-3
Checking the spark plug ................. 6-5
Engine oil ....................................... 6-6
Cleaning the air filter element ........ 6-8
Cleaning the spark arrester ............ 6-9
Adjusting the carburetor ............... 6-10
Adjusting the engine idling
speed ........................................ 6-11
Adjusting the throttle cable free
play ........................................... 6-11
Valve clearance ............................ 6-12
Tires ............................................. 6-12
Spoke wheels ............................... 6-14
Accessories and replacement
parts .......................................... 6-14
Adjusting the clutch free play ....... 6-14Adjusting the brake lever free
play ........................................... 6-15
Adjusting the brake pedal free
play ........................................... 6-16
Checking the front and rear brake
shoes ........................................ 6-16
Drive chain slack .......................... 6-17
Cleaning and lubricating the
drive chain ................................ 6-19
Checking and lubricating the
cables ....................................... 6-19
Checking and lubricating the
throttle grip and cable ............... 6-20
Checking and lubricating the
brake and shift pedals .............. 6-20
Checking and lubricating the
brake lever ................................ 6-20
Checking and lubricating the
sidestand .................................. 6-21
Lubricating the swingarm
pivots ........................................ 6-21
Checking the front fork ................. 6-21
Checking the steering .................. 6-22
Checking the wheel bearings ....... 6-23
Battery ......................................... 6-23
Replacing the fuse ....................... 6-25
Supporting the motorcycle ........... 6-25
Front wheel .................................. 6-26
Rear wheel ................................... 6-28
Troubleshooting ........................... 6-29
Troubleshooting chart .................. 6-30U1P682E0.book Page 1 Wednesday, May 23, 2007 9:34 AM

1-1
1
SAFETY INFORMATION
EAU39313
Safe riding

Always make pre-operation
checks. Careful checks may help
prevent an accident.


This motorcycle is designed for off-
road use only, therefore, it is illegal
to operate it on public streets,
roads, or highways, even a dirt or
gravel one. Off-road use on public
lands may be illegal. Please check
local regulations before riding.


This motorcycle is designed to car-
ry the operator only. No passen-
gers.


Many accidents involve inexperi-
enced operators.
Make sure that the operator is
qualified and that you only lend
your motorcycle to other quali-
fied operators.
Know your skills and limits.
Staying within your limits may
help you to avoid an accident.


Many accidents have been caused
by error of the motorcycle opera-
tor. A typical error made by the op-
erator is veering wide on a turn
due to EXCESSIVE SPEED or un-dercornering (insufficient lean an-
gle for the speed). Never travel
faster than warranted by condi-
tions.


Ride cautiously in unfamiliar ar-
eas. You may encounter hidden
obstacles that could cause an ac-
cident.


The posture of the operator is im-
portant for proper control. The op-
erator should keep both hands on
the handlebar and both feet on the
operator footrests during operation
to maintain control of the motor-
cycle.


Never ride under the influence of
alcohol or other drugs.


Be sure the transmission is in neu-
tral before starting the engine.
Protective apparel
The majority of fatalities from motor-
cycle accidents are the result of head
injuries. The use of a safety helmet is
the single most critical factor in the pre-
vention or reduction of head injuries.


Always wear an approved helmet.


Wear a face shield or goggles.
Wind in your unprotected eyes
could contribute to an impairment
of vision that could delay seeing a
hazard.


The use of a jacket, heavy boots,
trousers, gloves, etc., is effective in
preventing or reducing abrasions
or lacerations.


Never wear loose-fitting clothes,
otherwise they could catch on the
control levers, footrests, or wheels
and cause injury or an accident.


Never touch the engine or exhaust
system during or after operation.
They become very hot and can
cause burns. Always wear protec-
tive clothing that covers your legs,
ankles, and feet.
Modifications
Modifications made to this motorcycle
not approved by Yamaha, or the re-
moval of original equipment, may ren-
der the motorcycle unsafe for use and
may cause severe personal injury.
Modifications may also make your
motorcycle illegal to use.
U1P682E0.book Page 1 Wednesday, May 23, 2007 9:34 AM

SAFETY INFORMATION
1-2
1 Loading and accessories
Adding accessories to your motorcycle
can adversely affect stability and han-
dling if the weight distribution of the
motorcycle is changed. To avoid the
possibility of an accident, use extreme
caution when adding accessories to
your motorcycle. Use extra care when
riding a motorcycle that has added ac-
cessories. Here are some general
guidelines to follow if adding accesso-
ries to your motorcycle:
Loading


The weight of the operator must
not exceed 40 kg (88 lb).


Accessory weight should be kept
as low and close to the motorcycle
as possible. Make sure to distrib-
ute the weight as evenly as possi-
ble on both sides of the motorcycle
to minimize imbalance or instabili-
ty.


Shifting weights can create a sud-
den imbalance. Make sure that ac-
cessories are securely attached to
the motorcycle before riding.
Check accessory mounts fre-
quently.


Never attach any large or heavy
items to the handlebar, front fork,
or front fender.
Accessories
Genuine Yamaha accessories have
been specifically designed for use on
this motorcycle. Since Yamaha cannot
test all other accessories that may be
available, you must personally be re-
sponsible for the proper selection, in-
stallation and use of non-Yamaha
accessories. Use extreme caution
when selecting and installing any ac-
cessories.
Keep these guidelines in mind for
mounting accessories in addition to
those provided under “Loading”.

Never install accessories or that
would impair the performance of
your motorcycle. Carefully inspect
the accessory before using it to
make sure that it does not in any
way reduce ground clearance or
cornering clearance, limit suspen-
sion travel, steering travel or con-
trol operation.
Accessories fitted to the handle-
bar or the front fork area can
create instability due to improperweight distribution or aerody-
namic changes. If accessories
are added to the handlebar or
front fork area, they must be as
lightweight as possible and
should be kept to a minimum.
Bulky or large accessories may
seriously affect the stability of
the motorcycle due to aerody-
namic effects. Wind may at-
tempt to lift the motorcycle, or
the motorcycle may become un-
stable in cross winds.
Certain accessories can dis-
place the operator from his or
her normal riding position. This
improper position limits the free-
dom of movement of the opera-
tor and may limit control ability,
therefore, such accessories are
not recommended.


Use caution when adding electri-
cal accessories. If electrical acces-
sories exceed the capacity of the
motorcycle’s electrical system, an
electric failure could result, which
could cause a dangerous loss of
engine power.
U1P682E0.book Page 2 Wednesday, May 23, 2007 9:34 AM

SAFETY INFORMATION
1-3
1Gasoline and exhaust gas


GASOLINE IS HIGHLY FLAMMA-
BLE:
Always turn the engine off when
refueling.
Take care not to spill any gaso-
line on the engine or exhaust
pipe(s)/muffler(s) when refuel-
ing.
Never refuel while smoking or in
the vicinity of an open flame.


Never start the engine or let it run
for any length of time in a closed
area. The exhaust fumes are poi-
sonous and may cause loss of
consciousness and death within a
short time. Always operate your
motorcycle in an area that has ad-
equate ventilation.


Always turn the engine off before
leaving the motorcycle unattended
and remove the key from the main
switch. When parking the motor-
cycle, note the following:
The engine and exhaust pipe(s)/
muffler(s) may be hot, therefore,
park the motorcycle in a placewhere pedestrians or children
are not likely to touch these hot
areas.
Do not park the motorcycle on a
slope or soft ground, otherwise it
may fall over.
Do not park the motorcycle near
a flammable source (e.g., a ker-
osene heater, or near an open
flame), otherwise it could catch
fire.


When transporting the motorcycle
in another vehicle, make sure that
it is kept upright and that the fuel
cock(s) are turned to “ON” or
“RES” (for vacuum type)/“OFF”
(for manual type). If the motorcycle
should lean over, gasoline may
leak out of the carburetor or fuel
tank.


If you should swallow any gaso-
line, inhale a lot of gasoline vapor,
or allow gasoline to get into your
eyes, see your doctor immediately.
If any gasoline spills on your skin
or clothing, immediately wash the
affected area with soap and water
and change your clothes.
U1P682E0.book Page 3 Wednesday, May 23, 2007 9:34 AM

DESCRIPTION
2-1
2
EAU10410
Left view
12 34 5
76
1. Fuel cock (page 3-5)
2. Throttle stop screw (page 6-11)
3. Air filter element (page 6-8)
4. Fuse (page 6-25)
5. Battery (page 6-23)
6. Engine oil drain bolt (page 6-6)
7. Shift pedal (page 3-2)
U1P682E0.book Page 1 Wednesday, May 23, 2007 9:34 AM

DESCRIPTION
2-2
2
EAU10420
Right view
4 65 32 1
1. Seat (page 3-7)
2. Fuel tank cap (page 3-3)
3. Spark plug cap (page 6-5)
4. Brake pedal (page 3-3)
5. Clutch adjusting screw (page 6-14)
6. Engine oil filler cap (page 6-6)U1P682E0.book Page 2 Wednesday, May 23, 2007 9:34 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-1
3
EAU40340
Main switch The main switch controls the ignition
system. The main switch positions are
described below.
EAU10630
ON
All electrical systems are supplied with
power, and the engine can be started.
The key cannot be removed.
EAU10660
OFF
All electrical systems are off. The key
can be removed.
EAU12347
Handlebar switches Left
Right
EAU12660
Engine stop switch “/”
Set this switch to “” before starting
the engine. Set this switch to “” to
stop the engine in case of an emergen-
cy, such as when the vehicle overturns
or when the throttle cable is stuck.
EAU12710
Start switch “”
Push this switch to crank the engine
with the starter.CAUTION:
ECA10050
See page 5-1 for starting instruc-tions prior to starting the engine.
1. Engine stop switch “/”
1. Start switch “”
1
U1P682E0.book Page 1 Wednesday, May 23, 2007 9:34 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-2
3
EAU39861
Speed limiter Your motorcycle was delivered with an
adjustable speed limiter. The speed
limiter keeps the throttle from fully
opening, even when the throttle grip is
turned to the maximum.
1. Loosen the locknut.
2. To increase the maximum engine
power available and the maximum
speed of the motorcycle, turn the
adjusting screw in direction (a). To
decrease the maximum engine
power available and the maximum
speed of the motorcycle, turn the
adjusting screw in direction (b).
3. Tighten the locknut.
WARNING
EWA14401
Improper adjustment of the speed
limiter could cause improper throttle
operation. You could lose control,
have an accident or be injured. Do
not turn the adjusting screw out
more than 25 mm (0.98 in). Always
make sure the throttle cable free
play is adjusted to 3.0–5.0 mm (0.12–0.20 in). (See page 6-11.)
EAU39850
Shift pedal This motorcycle is equipped with a con-
stant-mesh 3-speed transmission. The
shift pedal is located on the left side of
the engine. Neutral is at the bottom po-
sition.
1. Locknut
2. Adjusting screw
12
(b)
(a)
1. No more than 25 mm (0.98 in)
1
1. Shift pedal
U1P682E0.book Page 2 Wednesday, May 23, 2007 9:34 AM